Control of radiocircuits



Feb-25, i930?, A L. F. @ma $34954@ CONTROL OF RDIOCBCUITS Filed Feb. 24, 1,925

A 7 TRA/f Y.

`PatentedA Feb. 193 j l LEROY i?. DYER, or QUINCY, MASSACHUSETTS -coiiTRoL for' imniccritcnitrs 'Application inegi rehruaryai. 19,25. serial No. 11,2221. si

This invention. lrelates vto the control ot radiocircuits and more particularly to means for facilitating the tuning of related circuits.

The various systems of related `circuits.

which areemployed in radio communication for receivingv or transmitting signals, yare cony trolledsimilarly to .produce an optimum conditioiiiorany particular wave length or fre-` quencyby the adjustment ofcnev or'more tuningreactor-s andfbysuchadjustment a condi,-V

' tion;approachingresonance produced inthe individual .circuitk or circuits. Most systems in.k common use involve two or more coupled circuitS,one-of which includes the antenna or equivalent device. This .latter circuit n,has

markedly different electrical characteristics `from thosecomposed principally of lumped C apaciti-esand inductances, chiefly because of'` the distributed capacity of .the antennavitself. y,VVh'enever it is desired to bring each of the related circuits to its optimumconditiomeach ofy thetuning reactors with whichtlie circuits are commonly providedpsuch as a variable inductance or a variablecapacity, mustbe separately adjusted. Proposalsto interconnect mechanically several of these tuning dej vices have, however, usually not included tuning reactor for the antenna circuit because, Y.

for reasons statedabove,` it is not easy. to ndfa simpley relation between the necessary adjustments for the antenna circuit and thel AOther circuitswith which itis coupled.

, VIn aradio receivingsystem which yincludes two ormore circuits other than the',antenna..v circuit *shaving therein individual .tuningrre-A actorsk or controlling devices ,fit isfpossibla provided the design is such that; the vSettings of similarly calibrated dials attached to devicesvare identical for every frequency within the-range of thereceiver, mechanically to interconnect theniovable parts .ofwsaid devices so that they willmove in a predeter-l f `mined ratio, as gears, belted pulleys, yor. 45 by mountingrthein ,o n a singleishaft, and thus allow controlof these.devicestlirougfhla single f dial. vIn ari-.antenna gcircuit, on thelother hand, in which :the reactance and chicfly the inductance and ,capacity are distributed, fior .iria circuit. in1 clcsc :inductive rclatcnthcrctc; .thei.charactery ci. the-.variation .ofareactance with changes of frequencyis tc thev charactericf the Vsame vcratcn nfacrcut having only lumped'inductances andjcapaci-r cies .and it ,has heretofore bcn found-impossibflc t0' cbtainlikccr readily. @imparable dial ted; circuits Scttngs with. those of other, ric

@vacated .bym changing characteristics:

0f theantenna circuit..

' One ,object of the prccctcvcilton is lto PFOVlde. cnafrcngcmcntwhch' win facilitate lthe simultaneous tuning of' related circuits of different electrical characteristics.

lIt accordance with alfcctulccf thc nvcri, tion, a compensating reactor is Vplaced in one 'j of thccllcults whlch ,1s .ccnstrctcd and-.ac

ranged to supplant or to assistthe' usual tun.-

ingv device: ii'ibringiiigv said circuitJ 'approffii;y

mttclytq rcscnance when ,other arenileY with vill/whit .1S 'rclatcdhtrc bccntuned byl their tuningreactors. Y

circuit ntclrcsonance foriusewithsgnalsof a een particular'requcncyaredissimilar.tcandgnct; Y'

readilycomplrable Withltlie `changes required to canse thc 'timing reactor. .tlic circuit ccuplcd ltc 'f thc alltnnc: f circuit .tcf,b1,ng. tS

circuit imgltaiiQOusly toresonailce. v Clearly., j

th pcblcmls accentuated vivhcn vit i tempted to designa radio 'rece' ing set'sllltf blc for .use wthrivaricus .Aiiftlier"l feature, Of,the,in.v'entifoiirc1. ,tcs toan arrange ment for .simultanccusly.tuling'cctplcd cir cuits;c .neiofl which ncltdcs `tlc@S antenna, byrv f the. .Increment 'of Single cncatQr-'ccn fcllcfd device.V .11,1 lrthc illustrate d. arrangerufen tilcctlhA the circuit .which'includcS.'theicaitcnnacndthc.

crcuitcr circuits V,:Cumlc.cl th'crct'o 1 arc. .provided :with '-tlilic'gzfcactcrahctc ...cclldcn's'fs and, the Operating c. l etc mechanically@ y 7c' Another objectof the inventionis to devise single operator-controlled device. In the antenna circuit, a compensating reactor is provided which is arranged to for control by the single operator-controlled device and is also constructed and arranged so that the rate of change ofvreactance produced by movement of its relatively movable parts may be varied and determined in accordance with the characteristics of the particular antenna circuit.

In the illustrated construction, the compensating reactor has relatively movable elements and means for varying the rate of` nection with the accompanying drawings, in

which Fig. 1 isa ldiagram illustrating one spehciiicapplication of the invention to a'reiiex receiving system. Y

Fig. 2 is a diagram illustrating another application of the invention, to a simple crystal receiving system.

Fig. 3 shows one form of acompensating reactor constructed for use with my invention and mechanically coupled to a plurality ,of tuning condensers.

Although my inventionis applicable to radio circuits for various systems and for either receiving or transmitting systems, I shall, in order to facilitate explanation of the invention, discuss it only in connection with receiving systems and no limitation to any `particular system or class of systems should be implied therefrom.

In the particular system illustrated in Fig. 1, which I have found to be one effective application of the invention, the antenna circuit includes an` antenna 10, a compensating reactor in the form of a special adjustable v ariometer 12, an adjustableloading coil 14, thecoil 16 of a coupler, and a variablercondenser 18, the rotor plates of which arej grounded at l20. Y

Energy received in the antenna circuit is fed to the grid circuit of a vacuum tube 25, ofv the well-known three element type, through the other coil 22 of the coupler, and the circuit is tuned byv means of a variable condenser 24 bridged across said coil and connected at one terminal to the grid 26 of the tube and at the other. terminal to the filament 28of said tube. Direct current may be supplied to thefilament 28 from a suitable battery 30 under the control of a rheostat 32.

The circuit from the plate 34 of the vacuum tube 25 is arranged to be tuned by a variable condenser 36 in shunt with an inductance 38, both of which are bridged across Ya crystal 40 and the primary winding 42 of an audio frequency transformer. The plate circuit is completed through telephones 44 and a battery 46n to the filament 28.

The current flowing in the primary winding 42 induces a current in a secondary winding 48 of the audio frequency transformer which is fed baclrinto the grid circuit by bridging the terminals of the secondary winding 48 across a fixed condenser 50 in said grid circuit. Preferably a by-pass fixed condenser 52 is shunted across the telephones 44 andthe battery 46 while another by-pass fixed condenser 54 is shunted across the primary winding 42 of the audio frequency transformer. I Y

The tuning reactors 18, 24, and 36 and the compensating reactor 12 are arranged for control by a single operator-controlled device 56. Preferably the movable parts of said reactors are mechanically interconnected so that they will move in a predetermined ratio as, for example, by mounting the rotors ofthe condensers 18, 24, and 36'and the rotor of the compensating variometer 12 upon a single shaft, with the various rotors insulated from one another. i v

rIhe compensating reactormay be constructed as indicatedin Fig. 3 as a novel form of adjustable variometer having relatively movable electrical parts 60 and 68V constructed and arranged so that the rate of variation of reactance, here largely.v inductance, may be cont-rolled. To this end stator windings 60 and 62, which are-shownV as hollow hemispheres, are mounted upon adjustable supporting brackets 64 and 66 by means of which the position of one or both of said stator windings maybe adjusted to control the proportion of the flux produced thereby which is cut bya rotorV winding 68. In Vother words, adjustment of one of the electrical parts of the compensating reactor, here adjustment of the position of the stator windings 60 and 62, enables the operator to vary the rate of change of reactance produced by movementof the rotor winding 68-and hence its characteristic curve. vIn Vone adjusted position of the'stator windings, the incremental change of'r'eactancel may be'one `ohm for each degree of rotation, for example, producing a rate-of change' ofV one ohm per degree. In another position of adjustment 'of the stator windings, the rate may be three ohms per degree, but it will be understood that Vthese figures are merely illustrative and have no relationto any particular circuit. This rotorwinding is approximately spherical in form andis connected in series with and intermediate between the stator windings 60 and62.- The'rotor winding 68 may be supported for rotation upon a shaftico mis-,cec

Ajm'lfafi-iai in .rimangano-aaa pmt-ideama an operator-controlled device 72.".:The .conipensatingreactor-or*variometer is shown herey ScOnnected directly',to-.an'antenna 74;

y but /thi'sais merely.. indicative of its. position. inftheap articulan-circuit shown `in FigQ- 1I and vshould not ben-construed asafli'miting, itslfuse' to lsuch :a `position or Connection. .1 'llie:` particularv `form of kthe winding .illustrated may l ,gabe replaced'by other well-known typessuchv l. as thei figure 8?. type without' aiectingthe operation of the device. e l It f should be noted that .the compensating reactor need lnot providethe ftotalf'inductance' i@ used in tuning the antenna circuitfbut only a` ysuflicient amount to compensatestorthe'efect:

of the; .antenna upon .f the .circuit- YS-u'ilicient additional inductance; to, adapt the, receiver to theVyz required'wa'velength range is then provided by the series loadingcoil 14, tapped v i to secure fine variation.A

I nd it convenient so to arrange the stator windings 6() and 62 with respect to the rotorv winding 68 and the rotors vof the vari-V g able condensers 18, 24, and 36 than-when all of said condensers are set in a minimum position, the inductance of the compensating variometer will also be a minimumfor the particular angular positions Aof'the stator windings andV that, when the condensers arev set in a maximum position, the inductance of the variometer will also be a maximum for the particular ypositionsof the'stator windv ings.

determining the proper position of the stal tor windings of the compensating reactor or variometer so that saidvariometer will be veffective in 4connection with a particular c45; antenna is Vas follows :-`'Having placed the stator windings at some arbitary point such '-as, that indicated in thedrawings, a signal of low wave lengthshould kbe'tuned in Y by manipulation .of the operator-controlled i(21"51.deviceindicatedat 56 or at 72 and variation of theloading coil 14. The'position of the tap switch :for the inductance coil 14 should be l noted and then a signal'of high wave length tuned in. If, in tuning in the signal of .higher 5.31)'- wavelength, it is found necessary to 'increase'y the inductance of the coil 14, the stator windings of. the variometer should be moved to a position nearer' the rotor, but, if it is found necessary to vdecrease the inductance of the coil 14.at the higher wavelength, thenthe stator windings or' the compensating variometer should be adjusted to a position :E arther away from the rotor. This operation should be repeated for a. variety of wave FG'D lengths until a position of the stator windings is found at'which the settingof the tapped coil 14 will be the same for high and low and intermediate wave lengths.V .At this position,

' the compensating reactor willbecome eRec- "GS tive to perform the 'functions ,already de'-y One satisfactory and. practical method of j scribed so that-,ithe system; may be effectively tuned -simplyrby the operati-onof a single der.. 'vice56..-

The inventionvmay be applied` to many-circuitsyusing many combinations fof apparatus withoutK aiiecting the principlesinvolvedy One other applicatiomto-atwo circuit crystalv receiveremploying-a loosely -coupled antenna circuit andi a t-unedv secondary circuit, is shown" in-Fig.2.- lI-lere anantenna 7 6 `is connected through-the compensating reactor 78 and a tapped coil 80 'of a yar-io-couplerto anv adjustable condenser 82andthenceto `ground `84.

Another coil 86 ofthe vario-coupler is included' in :a secondarycircuit, tuned b v a variable Fatentof theUnited States is: v

1flnfa radio system having a plurality of y' circuits to .be tuned, tuningreactors for said circuits, each of saidreactors having. a:A Inovablepart the mechanical movement of which,

produces 'changes in reactance, one of said circuitsy having4 af distributed vreactance, a'

variable compensating reactor in the lastlmentioned circuit havingaimov'able part byv Y the; movements of which changes in its reademe-re i911@duced, :meanjafor 'varying the acc rate of .variation ingreactanceofthe compensating reactor :producedlby changes 1in .the rnechanicalposition of. its .movable part, yand means for ,mechanic/ally interconnecting the movable partszof said/timing` reactors and said@ compensating. reactor ,constructedl and arraiigedfl to movethem in. a predetermined ously tuning related circuitslof differentfele'ctrical characteristicscomprising mechanical- 1 aving. thus describedmyvinvention, kwhat l y.2, Ii/nfcombinatiomgmeans--fori simultane- I claim as new and seek to cover by Letters lycoupled,tuning reaetors,.said"means including. a compensating reactor in .one of y said circuits. having relatively lmovable electrical pantsone .of ywhich r isv adustable-to vary; the characteristic ,lcurve-o'f the reactor, said compensating reactor, being constructed and v arranged whensaid@adjustablepartihas been vpreliminarily adjusted, to bring saidv circuit to 'resonancev simultaneously lwith the! tuning .0f-the` other fcircuit by manipulationof its tuningjreactor.

I i3. ...In A combination, coupled y circuits, one of said circuits having a markedly distributed` reactance-,athe other of saidcircuits .having a substantially lumpedreact-ance, variablel tun'- e ifng ,reactors ink saidA circuits, .la si-ngleI operatq ing. means for l said react-ors arranged kto vary. them *iny ifa.; predetermined .-ratio, l a-:lfmpeIiSa-t-ns Ireact-0i" in .-.Sad-1St-men a tioneldi-circuit havingrelativelymovable coils,

and means 'or V varying the incremental changes in reactance of said compensating reactor produced by successive equal movements of one of the coils lconstructed and arranged to make said reactors simultaneously eiectiveto tune their circuits when moved by the single operating means. L i

4L. In combination, coupled circuits, one of said circuits having a markedly distributed reactance, the other of said circuits having a substantially lumped reactance, variable tuning reactors in said circuits, a compensating reactor in one of said circuits, a single operating means for said tuning and compensating reactorsv arranged to move them together equal amounts, and means to vary the resultant reactance lof the compensating 'reactor accompanying said movements to the Vend that the reactor in the same circuit will be enabled to bring its circuit to approximate resonance when resonance of the other circuity has been attained by adjustment of its tuning reactor.

5. In combination,inductively coupled circuits, one of said circuits having a markedly distributed capacity, the other of said circuits having a lumped capacity, variable tuning reactors in said circuits, a single operating means for said reactors arranged to vary them in a Vpredetermined ratio, a compensating indetuning effect of the distributed capacity in' the antenna. i

V8. A radio receiving system including an antenna circuit havinga tuning condenser anda compensating .variometer, means for varying the relative path of movement of the windings of said variometer to control the rate of change of `inducta-nce produced by relative movemento the windings, another circuit inductively coupled to said antenna circuit having a ltuning condenser, and a Vsingle operator-controlled dial connected mechanically to and arranged to control simultaneously said condensers and said variometer, thereby to Vtune both circuits for signals of any particular. wave length.

In testimony whereof I have signed my name to this speciication.

' LEROY vF. DYER.

ductor in said first-mentionedg circuit also Y controlled by said operating means, and means for varying the effect on the inductance of said compensating inductor produced by equal movements of said operating means whereby said reactors will be simultaneously eiiective to tune their circuits when moved by the single operating means.

6. In combination, means for tuning simultaneously related circuits of different electrical characteristics comprising tuning re-V actors in said circuits including a compensat ing reactor in one of said circuits having relatively movable windings, means for varying the amount of Y change in the combined re' actance of said windings produced by similar relative movements thereof, and a single operator-controlled device for bringing the circuits simultaneously intoan optimum condition for use with signals of a particular frequency, said device being arranged to control said tuning reactors and said compensatingV reactor. f

k7. A Vsingle dial control for' a radio receiving set arranged simultaneously to control Y and'bring to anoptimum condition for the reception of signals of any particular wave length the antenna circuit and anothercircuit by ,moving together both the tuning reactor in the latter circuit and also a compensating device in the antenna circuit, said compensating device having relatively movable parts and being provided'with means to vary the interaction of the parts in-similar positions of one'part, thereby to offset the 

